Laser fire control system small boat application

ABSTRACT

A small boat surface to surface weapon control system comprising search radar, TV camera, laser transmitter and a semi-active guided missile is disclosed. The target is initially located by radar scanning devices and the bearing is transferred to a television camera mechanism which is mounted on the same mast as the radar antenna. The television camera and a laser gun will then be pointed in the direction of the target. A blossom on a television screen which coincides with the image of the target indicates that the laser gun is on line with the target. The missile is fired and rides a reflected laser beam to the target.

limited States Patent Kearney, II

LASER FIRE CONTROL SYSTEM SMALL BOAT APPLICATION Inventor: Stuart D. Kearney, II, Severna Park,Md.

Assignee: The United States of America as Represented by the Secretary of the Navy Filed: July 28, 1969 Appl. No.: 846,313

US. Cl. 343/6 R, 343/6 TV, 244/3.l3 Int. Cl. G0ls 9/02, F41g 7/00 Field of Search 343/6 R, 6 TV;

References Cited UNITED STATES PATENTS Primary Examiner-T. H. Tubbesing Attorney-Edgar J. Brower and Thomas 0. Watson, Jr.

[ ABSTRACT A small boat surface to surface weapon control system comprising search radar, TV camera, laser transmitter and a semi-active guided missile is disclosed. The target is initially located by radar scanning devices and the bearing is transferred to a television camera mechanism which is mounted on the same mast as the radar antenna. The television camera and a laser gun will then be pointed in the direction of the target. A blossom on a television screen which coincides with the image of the target indicates that the laser gun is on line with the target. The missile is tired and rides a reflected laser beam to the target.

4 Claims, 2 Drawing Figures TARGET /7 SMALL SURFACE VESSEM PATENIEU M1821 I915 3. 754- ,2A9

TELEVISION DISPLAY FIG. 2

INVENTOR $TUART 0 KEARNEY H BY 7% 0. Ma).

ATTORNEY LASER FIRE CONTROL SYSTEM SMALL BOAT APPLICATION STATEMENT OF GOVERNMENT INTEREST The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION The invention relates to a fire control system for small boats and more particularly to a fire control system utilizing laser beam guidance means for missiles carrying warheads.

Increased emphasis has been placed recently on both the utilization of small boats and their associated fire power for coastal defense and incipient insurgency actions. Improvements in the fire power of small boats has been dormant since the use of PT boats in World War II. Torpedoes have limited versatility whilegun fire has a poor first shot kill probability.

The first control system described in this invention fulfills a small boat requirement by being versatile and light weight while still providing an inherent accuracy,

for the delivery of a medium size (12-50 lbs.) warhead. This fire power gives a small boat the impact of a inch, 38 caliber gun which is employed as first line armament by a 22 hundred ton Naval destroyer.

SUMMARY OF THE INVENTION The basic elements of the fire control system comprising the invention are the boats surface search radar, a TV camera for area display, a laser transmitter, and a semi-active guided missile. The boats surface radar seeks out, identifies and ranges a prospective target. A television camera presents the real world image of the target to an operator who brings the laser beam transmitted from the laser transmitter on target by coinciding the reflected laser beam appearing as a blossom on the television screen with the real world image of the target. Such a coincidence indicates that the laser beam is on target. The semi-active guided missile may be launched so as to intercept the path of the reflected laser beam which it will then follow to the target.

OBJECTS OF THE INVENTION An object of this invention is to provide a small surface vessel with fire power potentially equivalent to a destroyer.

Another object of this invention is to provide destroyer fire power capabilities to small surface vessels while still providing a versatile, light-weight, and accurate weapon control system.

Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 illustrates, in graphical form, a target vessel and an attacking vessel using the fire control system of the invention; and

FIG. 2 illustrates a television display on-board the attacking vessel using the weapon control system of the instant invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to FIG. 1, there is illustrated the functional relationship of the elements comprising the invention. A small surface vessel is adapted to carry a greatly increased fire power capability by the installation of missiles on its deck. The control of these missiles, which are capable of carrying medium size warheads, is the responsibility of the invention disclosed. The boat's surface search radar, which renders range and azimuth or bearing indications on a PP] type radar display, is used to initially detect a potential target, as illustrated by the parabolic antenna 11 and radar beam 12 of FIG. 1.

Upon detection of a potential target, a small television camera 13 may be focused on said target by adjusting the camera to the bearing of the parabolic rotating antenna 11. The television camera may be mounted in proximity with the boats radar antenna on the same mast. The camera will present a real world image as determined by light rays 14, on a television screen display within the ship.

Upon the initial detection and identification of the target, a laser transmitter 10 of a solid state type commonly known as an optical maser which is mounted on the same mast as the vessels radar antenna and television camera is used to establish a laser path to the target. The television camera 13 and laser transmitter 10 are mounted in proximity to the reflecting antenna of the ships radar system as illustrated in FIG. 1.

Referring now to FIG. 2, reference is made to laser beam blossom 19 which is created by the transmitted laser beam 15 reflecting from the target 17. A defense control crew on the small vessel employing the invention, may manipulate laser transmitter 10 so as to cause a coincidence between laser blossom l9 and target 18. Upon coincidence, an operator is assured that the laser transmitter 13 is directing laser beam 15 on target.

Activation of the missile launcher will cause the missile to be projected along a trajectory 16 which will intercept the reflection of laster beam 15. A laser beam detector mounted in the head of the missile is activated upon the missiles interception of the reflected laser beams. The detector is effective to cause the missile to follow the reflected laser beam to the target. 1

The laser beam detector mounted in the head of the guided missile may be of the rotation field type or it may be a four element photodiode. The four element photodiode is more ideally suited for laser centering systems. It comprises four elements each consisting of a silicon Schottky photodiode. Mounted together the diodes have an active area diameter of 0.450 inches. Each of the four quadrants of the active area are separated by a spacing of 0.005 inches. Position of a light spot on the photodiode is determined by the current in each element. By use of this detector and associate ser vo-mechanisms, the missile rides the beam on a collision course to the target.

Both the television camera and laser transmitter may be manually maintained on target. The television camera and the laser transmitter are stabilized on the boat s mast to permit the line of sight from boat to target to remain on target. I

The laser weapons control system disclosed fulfills the requirement for a light-weight missile fire control system for small boats. It further provides reliability,

easy and minimum maintenance and relatively low cost. These advantages are inherent in the system because its subcomponents are reliable field performance proven equipment.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings.

What is claimed is:

1. A weapons control system for small boats comprising:

search radar apparatus for sighting and ranging potential targets;

a television camera responsive to a command signal created in response to sighting of a potential target on said radar to align said camera with the receiving antenna bearing of said radar apparatus;

a laser transmitter mounted in proximity to said television camera and responsive to movements of said camera to align itself along the same bearing assumed by said camera; and

laser beam detector means mounted in nose of a guidable missile responsive to a target reflected laser beam to cause said missile to ride said beam to said target. g

2. The weapon control system of claim 1 further comprising a television receiver responsive to said television camera to diaplay images of said target and said reflected laser beam, whereby a coincidence between the target image and the reflected laser beam image indicates said laser transmitter is on target.

3. The weapons control system of claim 2 wherein said laser beam detector means comprises a four quadrant silicon detector.

4. A method for controlling fire power of surface craft utilizing search radar apparatus, a television camera, a laser transmitter rotateably mounted on a mast, a television receiver responsive to said camera, a guidable missile, and a laser beam detector means mounted in nose of said missile, comprising the steps of:

detecting a target by means of said search radar apparatus;

rotating the television camera to assume bearing of the receiving antenna of said radar apparatus; rotating the laser transmitter to assume the bearing of said television camera;

manually adjusting said laser transmitter on target by coinciding target image and reflected laser beam blossom on said television screen; and

launching the guidable missile so it will intercept the reflected laser beam and ride it to the target.

l 4K 8* 1K 

1. A weapons control system for small boats comprising: search radar apparatus for sighting and ranging potential targets; a telEvision camera responsive to a command signal created in response to sighting of a potential target on said radar to align said camera with the receiving antenna bearing of said radar apparatus; a laser transmitter mounted in proximity to said television camera and responsive to movements of said camera to align itself along the same bearing assumed by said camera; and laser beam detector means mounted in nose of a guidable missile responsive to a target reflected laser beam to cause said missile to ride said beam to said target.
 2. The weapon control system of claim 1 further comprising a television receiver responsive to said television camera to diaplay images of said target and said reflected laser beam, whereby a coincidence between the target image and the reflected laser beam image indicates said laser transmitter is on target.
 3. The weapons control system of claim 2 wherein said laser beam detector means comprises a four quadrant silicon detector.
 4. A method for controlling fire power of surface craft utilizing search radar apparatus, a television camera, a laser transmitter rotateably mounted on a mast, a television receiver responsive to said camera, a guidable missile, and a laser beam detector means mounted in nose of said missile, comprising the steps of: detecting a target by means of said search radar apparatus; rotating the television camera to assume bearing of the receiving antenna of said radar apparatus; rotating the laser transmitter to assume the bearing of said television camera; manually adjusting said laser transmitter on target by coinciding target image and reflected laser beam blossom on said television screen; and launching the guidable missile so it will intercept the reflected laser beam and ride it to the target. 